Poll: Sestak Takes Lead Against Toomey

The new Rasmussen poll of the Pennsylvania Senate race shows Democratic Rep. Joe Sestak jumping into the lead over Republican former Rep. Pat Toomey, in the wake of Sestak's upset victory over incumbent Sen. Arlen Specter in Tuesday's Democratic primary.

The numbers: Sestak 46%, Toomey 42%. The poll of likely voters has a Â±4.5% margin of error. Two weeks ago, Rasmussen had Toomey edging out Sestak by 42%-40%, and also had Toomey leading Specter by a much wider 50%-38%. The TPM Poll Average, composed entirely of pre-primary data except for this new survey, has Toomey ahead of Sestak by 39.6%-37.7%, with Sestak clearly gaining since March.

The pollster's analysis finds that Democratic voters are rallying around their nominee, now that the primary is over: "Support for Sestak among Democrats in Pennsylvania jumped from 64% to 80% since the Primary election. Toomey's support among GOP voters in the state has changed little over the past two weeks."

As you can see from the graph below, Toomey's support has stayed within a particular range, while Sestak's support began picking up steadily since March. This is quite similar to the Democratic primary, in which Specter's support stayed roughly static and Sestak steadily and dramatically picked up undecided voters beginning in March.